The present invention relates to a boom of a laying or placement mechanism of a bridge laying vehicle, wherein the laying mechanism is composed of a placement arm and the boom. The present invention also relates to a method of moving a boom of a bridge laying vehicle into a vehicle transport position.
The present invention finds application on, in particular, military bridge laying vehicles that can transport and lay bridge elements. The laying or placement vehicles can be wheeled or chained vehicles. Laying vehicles are generally provided with a placement arm, which is in particular disposed at the front end of the vehicle, but can also be disposed at the rear end. In this connection, the placement arm serves for the laying or placement of the bridge elements; in other words, the bridge elements can be deposited and again picked up via the placement arm. In addition, such vehicles are provided with a boom, which is in particular disposed at the rear of the vehicle, but can also be disposed at the front. The boom is generally provided with locking elements, such as, for example, a bolt locking mechanism via which the bridge elements can be locked in position, raised and held. Such a bridge laying vehicle is described, for example, in U.S. Pat. No. 5,067,191 or U.S. Pat. No. 5,937,468. The boom is generally moved by means of an adjustment device, such as a hydraulic cylinder.
The drawback of the known configurations is that only bridge elements having a single prescribed length can be transported and placed. Bridge elements having a different length cannot be transported in particular for the reason that otherwise the center of gravity of the vehicle together with the bridge element is shifted, so that it is no longer possible to travel in a stable position. For this reason, the laying vehicle, together with the boom, must be adapted to or coordinated with the bridge elements that are to be transported and placed.
A further drawback is that with modern laying vehicles, supplemental armoring, such as, for example, a protection against mines, is provided in the front region of the vehicle and shifts the center of gravity of the vehicle. Thus, however, the laying mechanism, which is composed of a placement arm and a boom, must also be structurally adapted, so that a subsequent provision of a supplemental armoring on the vehicle is possible only at very great expense if there is to be no loss of stability, especially at the traveling speed.
A further drawback of the known laying vehicles is that the boom projects upwardly and toward the rear or toward the front, thus making transport of the bridge laying vehicle, for example via a towing vehicle, more difficult. This problem, and a possible solution, are provided in DE 10 2005 041 493 B3. The rear boom described in this document can be brought into a vehicle transport position for transport of the vehicle. The boom is provided with an arm that is designated as a rear beam and that is pivotably disposed on a base member that is designated as a rear frame. The base member is fixedly connected to the vehicle. During the laying or placement of a bridge element, the arm can be pivoted by means of a hydraulic cylinder. The cylinder is supported against a traverse or cross beam that is pivotably disposed on the base member, whereby during the placement process the pivoting movement is prevented by a bolt fixation means. If the boom is brought into a vehicle transport position, the traverse can be lowered via the cylinder, so that in the vehicle transport position the boom has a lesser extension in the vertical direction while having the same extension in the longitudinal direction of the vehicle.
A drawback of the configuration described above is that the arm cannot be moved downwardly to an adequate extent since it is still joined or linked to the base member. In addition, the transition into the vehicle transport position is very complicated, since bolts have to be repeatedly relocated. Furthermore, it is also not possible to shift the center of gravity for accommodating different bridge elements or when a supplemental armoring is provided.
It is an object of the present invention to design a boom with an increased moveability in order, for example, to better move it into a vehicle transport position.